.middle{
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.input-3{
  width: 60px;
  height: 60px;
  background: none;
  border-radius: 50%;
  border: 4px solid #111;
  box-sizing: border-box;/*限制元素内元素大小不超过设置的宽高*/
  outline: none;
  transition: width 0.4s ease-in-out,
              border-radius 0.8s ease-in-out,
              padding 0.2s;
  transition-delay: 0.4s;
  color: black;
  font-size: 20px;
}

.inclicked{
  width: 360px;
  border-radius: 0;
  padding: 0 15px;
  padding-right: 40px;
}

.input3-btn{
  position: absolute;
  width: 60px;
  height: 60px;
  top: 0;
  right: 0;
  box-sizing: border-box;
  background: none;
  border: none;
  outline: none;
  cursor: pointer;
}

.input3-btn::before{
  content: "";
  width: 4px;
  height: 25px;
  background: black;
  position: absolute;
  transform: rotate(-45deg);
  bottom: -16px;
  right: -6px;
  transition: 0.3s;
}

.close::before,.close::after{
  content: "";
  width: 4px;
  height: 34px;
  background: black;
  position: absolute;
  bottom: 12px;
  right: 28px;
}

.close::before{
  transform: rotate(-45deg);
}

.close::after{
  transform: rotate(45deg);
}